Articulation mechanisms for surgical instruments such as for use in robotic surgical systems

ABSTRACT

An articulation assembly for a surgical instrument, surgical instrument including the same, and robotic surgical system including a surgical robot and the surgical instrument including the articulation assembly. The articulation assembly includes lead screw assemblies each including a lead screw and a collar operably engaged about the lead screw such that rotation of the lead screw translates the collar about the lead screw. Articulation cables are operably coupled to the collars of the lead screw assemblies such that proximal movement of one of the collars about the respective lead screw tensions the corresponding articulation cable and such that distal movement of one of the collars about the respective lead screw de-tensions the corresponding articulation cable. Proximal gear assemblies are coupled to the lead screws. Coupling gears couple pairs of the proximal gear assemblies with one another to maintain a pre-tension on the corresponding articulation cables.

BACKGROUND Technical Field

The present disclosure relates to surgical instruments and, morespecifically, to articulation mechanisms for surgical instruments suchas, for example, for use in robotic surgical systems.

Background of Related Art

Robotic surgical systems are increasingly utilized in various differentsurgical procedures. Some robotic surgical systems include a consolesupporting a robotic arm. One or more different surgical instruments maybe configured for use with the robotic surgical system and selectivelymountable to the robotic arm. The robotic arm provides one or moreinputs to the mounted surgical instrument to enable operation of themounted surgical instrument.

The number, type, and configuration of inputs provided by the roboticarm of a robotic surgical system are constraints in the design ofsurgical instruments configured for use with the robotic surgicalsystem. That is, in designing a surgical instrument compatible formounting on and use with the robotic arm of a robotic surgical system,consideration should be taken in determining how to utilize theavailable inputs provided by the robotic arm to achieve the desiredfunctionality of the surgical instrument.

SUMMARY

As used herein, the term “distal” refers to the portion that is beingdescribed which is further from a surgeon, while the term “proximal”refers to the portion that is being described which is closer to asurgeon. The terms “about,” substantially,” and the like, as utilizedherein, are meant to account for manufacturing, material, environmental,use, and/or measurement tolerances and variations. Further, to theextent consistent, any of the aspects described herein may be used inconjunction with any or all of the other aspects described herein.

Provided in accordance with aspects of the present disclosure is anarticulation assembly for a surgical instrument including first, second,third, and fourth proximal gear assemblies arranged such that the firstand third proximal gear assemblies and the second and fourth proximalgear assemblies are diagonally-opposed relative to one another. Thearticulation assembly further includes first, second, third, and fourthdistal gear assemblies coupled to the respective first, second, third,and fourth proximal gear assemblies and arranged such that the first andthird distal gear assemblies and the second and fourth distal gearassemblies are diagonally-opposed relative to one another. The first andsecond distal gear assemblies are oppositely-configured relative to thethird and fourth distal gear assemblies. A first coupling gear couplesthe first and third proximal gear assemblies such that an input to thefirst proximal gear assembly effects similar outputs from the first andthird proximal gear assemblies to the first and third distal gearassemblies, respectively, which, in turn, provide opposite outputs dueto the opposite configuration of the first and third distal gearassemblies. A second coupling gear couples the second and fourthproximal gear assemblies such that an input to the second proximal gearassembly effects similar outputs from the second and fourth proximalgear assemblies to the second and fourth distal gear assemblies,respectively, which, in turn, provide opposite outputs due to theopposite configuration of the second and fourth distal gear assemblies.

In an aspect of the present disclosure, each of the first, second,third, and fourth proximal gear assemblies includes a gear shaftdefining an output, and a spur gear engaged about the gear shaft. Insuch aspects, the first coupling gear is disposed in meshed engagementwith the spur gear of the first and third proximal gear assemblies andthe second coupling gear is disposed in meshed engagement with the spurgear of the second and fourth proximal gear assemblies.

In another aspect of the present disclosure, a first gear set operablycouples the first and third proximal gear assemblies with the firstcoupling gear. The first gear set is configured to amplify or attenuatethe outputs from the first and third proximal gear assemblies relativeto the input to the first proximal gear assembly. Additionally oralternatively, a second gear set operably couples the second and fourthproximal gear assemblies with the second coupling gear. The second gearset is configured to amplify or attenuate the outputs from the secondand fourth proximal gear assemblies relative to the input to the secondproximal gear assembly.

In still another aspect of the present disclosure, each of the first,second, third, and fourth distal gear assemblies includes a lead screwand a collar operably engaged about the lead screw such that rotation ofthe lead screw translates the collar to provide the output.

In yet another aspect of the present disclosure, the lead screws of thefirst and second lead screw assemblies define a first thread-pitch andthe lead screws of the third and fourth lead screw assemblies define asecond thread-pitch opposite the first thread-pitch, thereby definingthe opposite configurations of the first and third distal gearassemblies and the opposite configurations of the second and fourthdistal gear assemblies.

In still yet another aspect of the present disclosure, the articulationassembly further includes a proximal base assembly, an intermediate baseassembly, and a distal base assembly. In such aspects, the first,second, third, and fourth proximal gear assemblies extend between theproximal and intermediate base assemblies, and the first, second, third,and fourth distal gear assemblies extend between the intermediate anddistal base assemblies.

In another aspect of the present disclosure, the articulation assemblyfurther includes first, second, third, and fourth articulation cablescoupled to the outputs of the respective first, second, third, andfourth distal gear assemblies.

A surgical instrument provided in accordance with the present disclosureincludes a housing, a shaft extending distally from the housing andincluding an articulating section, an end effector assembly extendingdistally from the shaft, and an articulation assembly disposed withinthe housing. The articulation assembly is configured to articulate theend effector assembly relative to the housing via first, second, third,and fourth articulation cables extending through the shaft. Thearticulation assembly may include the aspects and features of any of thearticulation assemblies detailed above or otherwise detailed herein andis configured such that the outputs of the first, second, third andfourth distal gear assemblies are coupled to the first, second, third,and fourth articulation cables, respectively. In aspects, the endeffector assembly includes first and second jaw members. At least thefirst jaw member is movable relative to the second jaw member from aspaced-apart position to an approximated position to grasp tissuetherebetween.

A robotic surgical system provided in accordance with the presentdisclosure includes a surgical robot including a robotic arm configuredto provide first and second rotational outputs. The robotic surgicalsystem further includes a surgical instrument releasably mountable onthe robotic arm, the surgical instrument includes an articulationassembly and may include any of the aspects and features of the surgicalinstruments detailed above or otherwise herein. The articulationassembly is configured to receive the first and second rotationaloutputs from the robotic arm and provide outputs coupled to thearticulation cables for selectively articulating the end effectorassembly.

Another articulation assembly provided in accordance with aspects of thepresent disclosure includes first, second, third, and fourth lead screwassemblies each including a lead screw and a collar operably engagedabout the lead screw such that rotation of the lead screw translates thecollar about the lead screw. The articulation assembly further includesfirst, second, third and fourth articulation cables operably coupled tothe collars of the first, second, third, and fourth lead screwassemblies, respectively, such that proximal movement of one of thecollars about the respective lead screw tensions the correspondingarticulation cable and such that distal movement of one of the collarsabout the respective lead screw de-tensions the correspondingarticulation cable. First, second, third and fourth proximal gearassemblies are coupled to the lead screws of the first, second, third,and fourth lead screw assemblies, respectively. A first coupling gearcouples the first and third proximal gear assemblies with one another tomaintain a pre-tension on the first and third articulation cables. Asecond coupling gear couples the second and fourth proximal gearassemblies with one another to maintain a pre-tension on the second andfourth articulation cables.

In an aspect of the present disclosure, the lead screws of the first andthird lead screw assemblies define opposite thread-pitches relative toone another and the lead screws of the second and fourth lead screwassemblies define opposite thread-pitches relative to one another.

In another aspect of the present disclosure, the first coupling gearcouples the first and third proximal gear assemblies such that the leadscrews of the first and third lead screw assemblies are rotated insimilar directions and, in aspects, such that the collars of the firstand third lead screw assemblies are moved in opposite directions. Thesecond coupling gear couples the second and fourth proximal gearassemblies such that the lead screws of the second and fourth lead screwassemblies are rotated in similar directions and, in aspects, such thatthe collars of the second and fourth lead screw assemblies are moved inopposite directions.

In yet another aspect of the present disclosure, the articulationassembly further includes a proximal base assembly, an intermediate baseassembly, and a distal base assembly. The first, second, third, andfourth proximal gear assemblies extend between the proximal andintermediate base assemblies, and the first, second, third, and fourthdistal gear assemblies extend between the intermediate and distal baseassemblies.

In still another aspect of the present disclosure, each of the first,second, third, and fourth proximal gear assemblies includes a gear shaftdefining an output configured to drive rotation of the correspondinglead screw, and a spur gear engaged about the gear shaft. In suchaspects, the first coupling gear is disposed in meshed engagement withthe spur gear of the first and third proximal gear assemblies and thesecond coupling gear is disposed in meshed engagement with the spur gearof the second and fourth proximal gear assemblies.

In still yet another aspect of the present disclosure, a first gear setoperably couples the first and third proximal gear assemblies with thefirst coupling gear and is configured to amplify or attenuate theoutputs from the first and third proximal gear assemblies to thecorresponding lead screws relative to the input to the first proximalgear assembly. A second gear set operably couples the second and fourthproximal gear assemblies with the second coupling gear and is configuredto amplify or attenuate the outputs from the second and fourth proximalgear assemblies to the corresponding lead screws relative to the inputto the second proximal gear assembly.

A surgical instrument including the articulation assembly according toany of the above aspects and a robotic surgical system including thesurgical instrument are also provided in accordance with aspects of thepresent disclosure.

Another articulation assembly for a surgical instrument provided inaccordance with aspects of the present disclosure includes a first baseassembly, a second base assembly, a first lead screw assembly, a firstarticulation cable, and a first set screw. The first lead screw assemblyextends between the first and second base assemblies and includes afirst lead screw and a first collar operably engaged about the firstlead screw such that rotation of the first lead screw translates thefirst collar about the first lead screw. The first lead screw defines aproximal input end and a distal dock end. The proximal input end isrotatably received within the first base assembly and the distal dockend is rotatably received within the second base assembly. The firstarticulation cable is operably coupled to the first collar such thatproximal movement of the first collar about the first lead screwtensions the first articulation cable and such that distal movement ofthe first collar about the first lead screw de-tensions the firstarticulation cable. The first set screw is threadingly engaged withinthe second base assembly and operably coupled to the distal dock end ofthe first lead screw such that proximal rotational driving of the firstset screw relative to the second base assembly urges the first leadscrew proximally, thereby urging the first collar proximally to increasetension on the first articulation cable.

In an aspect of the present disclosure, the second base assemblyincludes at least one first bushing that receives the distal dock end ofthe first lead screw. In such aspects, proximal rotational driving ofthe first set screw urges the first set screw into contact with thefirst bushing to thereby urge the first lead screw proximally.

In another aspect of the present disclosure, the first set screw isoperably engaged within a first internally-threaded nut disposed withinthe second base assembly.

In still another aspect of the present disclosure, the articulationassembly includes a second lead screw assembly extending between thefirst and second base assemblies, a second articulation cable, and asecond set screw. The second lead screw assembly includes a second leadscrew and a second collar operably engaged about the second lead screwsuch that rotation of the second lead screw translates the second collarabout the second lead screw. The second lead screw defines a proximalinput end and a distal dock end. The proximal input end is rotatablyreceived within the second base assembly and the distal dock end isrotatably received within the second base assembly. The secondarticulation cable is operably coupled to the second collar such thatproximal movement of the second collar about the second lead screwtensions the second articulation cable and such that distal movement ofthe second collar about the second lead screw de-tensions the secondarticulation cable. The second set screw is threadingly engaged withinthe second base assembly and operably coupled to the distal dock end ofthe second lead screw such that proximal rotational driving of thesecond set screw relative to the second base assembly urges the secondlead screw proximally, thereby urging the second collar proximally toincrease tension on the second articulation cable.

In yet another aspect of the present disclosure, the articulationassembly further includes a first proximal gear assembly operablycoupled to the proximal input end of the first lead screw assembly. Thefirst proximal gear assembly is configured to drive rotation of thefirst lead screw to thereby translate the first collar along the firstlead screw to tension or de-tension the first articulation cable.

In still yet another aspect of the present disclosure, the articulationassembly further includes a third base assembly. In such aspects, thefirst proximal gear assembly extends between the first and third baseassemblies.

In another aspect of the present disclosure, the first proximal gearassembly includes a first gear shaft including an input end configuredto receive an input and an output end configured to drive rotation ofthe first lead screw according to the input received at the input end.

In another aspect of the present disclosure, the first proximal gearassembly includes a first gear set configured to amplify or attenuatethe output from the first proximal gear assemblies to the first leadscrew assembly relative to an input to the first proximal gear assembly.

Another surgical instrument including the articulation assemblyaccording to any of the above aspects and a robotic surgical systemincluding the surgical instrument are also provided in accordance withaspects of the present disclosure. In aspects, the end effector assemblyof the surgical instrument includes first and second jaw members. Atleast the first jaw member is movable relative to the second jaw memberfrom a spaced-apart position to an approximated position to grasp tissuetherebetween.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects and features of the present disclosure are describedhereinbelow with reference to the drawings wherein like numeralsdesignate identical or corresponding elements in each of the severalviews.

FIG. 1A is a perspective view of an articulation assembly, shaft, andend effector assembly of a surgical instrument provided in accordancewith the present disclosure configured for mounting on a robotic arm ofa robotic surgical system;

FIG. 1B is a schematic illustration of an exemplary robotic surgicalsystem configured to releasably receive the surgical instrument of FIG.1A;

FIG. 2 is a rear, perspective view of the articulation assembly of thesurgical instrument of FIG. 1A, with portions removed;

FIG. 3 is an exploded, perspective view of the articulation assembly ofthe surgical instrument of FIG. 1A;

FIG. 4 is a side, perspective view of a proximal portion of thearticulation assembly of FIG. 2;

FIG. 5 is a longitudinal, cross-sectional view taken along section line“5-5” of FIG. 1A;

FIG. 6 is a transverse, cross-sectional view taken along section line“6-6” of FIG. 2;

FIG. 7 is a transverse, cross-sectional view taken along section line“7-7” of FIG. 2;

FIG. 8 is a top, front, perspective view of the articulation assembly ofFIG. 2 with portions removed, illustrating actuation thereof in a firstmanner;

FIG. 9 is a top, front, perspective view of the articulation assembly ofFIG. 2 with portions removed, illustrating actuation thereof in a secondmanner;

FIGS. 10 and 11 are side, perspective view of the articulation assemblyof FIG. 2 with portions removed, illustrating pre-tensioning andassembly of the articulation assembly of the surgical instrument of FIG.1A;

FIG. 12 is a front, perspective view of another surgical instrumentprovided in accordance with the present disclosure configured formounting on a robotic arm of a robotic surgical system;

FIG. 13 is a rear, perspective view of a proximal portion of thesurgical instrument of FIG. 12;

FIG. 14 is a side, perspective view of a portion the surgical instrumentof FIG. 12 with an outer housing half removed to illustrate internalcomponents therein;

FIG. 15 is transverse, cross-sectional view taken along section line“15-15” of FIG. 12;

FIG. 16 is an enlarged view of the area of detail indicated as “16” inFIG. 15;

FIG. 17 is a side, perspective view of another articulation assembly,with portions removed, provided in accordance with the presentdisclosure configured for use with a surgical instrument for mounting ona robotic arm of a robotic surgical system; and

FIG. 18 is a rear, perspective view of the articulation assembly of FIG.17.

DETAILED DESCRIPTION

Referring to FIG. 1A, a surgical instrument 10 provided in accordancewith the present disclosure generally includes a housing (not shown;similar to housing 502 of surgical instrument 500 (FIGS. 12-16)), ashaft 30 extending distally from the housing, an end effector assembly40 extending distally from shaft 30, and a gearbox assembly 100 disposedwithin the housing and operably associated with end effector assembly40. Instrument 10 is detailed herein as an articulating electrosurgicalforceps configured for use with a robotic surgical system, e.g., roboticsurgical system 1000 (FIG. 1B). However, the aspects and features ofinstrument 10 provided in accordance with the present disclosure,detailed below, are equally applicable for use with other suitablesurgical instruments and/or in other suitable surgical systems.

Shaft 30 of instrument 10 includes a proximal segment 32, a distalsegment 34, and an articulating section 36 disposed between the proximaland distal segments 32, 34, respectively. Articulating section 36includes one or more articulating components 37, e.g., links, joints,etc. A plurality of articulation cables 38 (see also FIG. 3), e.g., four(4) articulation cables, or other suitable actuators, extend througharticulating section 36. More specifically, articulation cables 38 areoperably coupled to distal segment 34 of shaft 30 at the distal endsthereof and extend proximally from distal segment 34 of shaft 30,through articulating section 36 of shaft 30 and proximal segment 32 ofshaft 30, and into the housing, wherein articulation cables 38 operablycouple with articulation sub-assembly 200 of gearbox assembly 100 toenable selective articulation of distal segment 34 (and, thus endeffector assembly 40) relative to proximal segment 32 and the housing,e.g., about at least two axes of articulation (yaw and pitcharticulation, for example). Articulation cables 38 are arranged todefine a generally square configuration, although other suitableconfigurations are also contemplated.

With respect to articulation of end effector assembly 40 relative toproximal segment 32 of shaft 30, actuation of articulation cables 38 iseffected in pairs. More specifically, in order to pitch end effectorassembly 40, the upper pair of articulation cables 38 are actuated in asimilar manner while the lower pair of articulation cables 38 areactuated in a similar manner relative to one another but an oppositemanner relative to the upper pair of articulation cables 38 (see alsoFIG. 3). With respect to yaw articulation, the right pair ofarticulation cables 38 are actuated in a similar manner while the leftpair of articulation cables 38 are actuated in a similar manner relativeto one another but an opposite manner relative to the right pair ofarticulation cables 38 (see also FIG. 3).

Continuing with reference to FIG. 1A, end effector assembly 40 includesfirst and second jaw members 42, 44, respectively. Each jaw member 42,44 includes a proximal flange portion 43 a, 45 a and a distal bodyportion 43 b, 45 b, respectively. Distal body portions 43 b, 45 b defineopposed tissue-contacting surfaces 46, 48, respectively. Proximal flangeportions 43 a, 45 a are pivotably coupled to one another about a pivot50 and are operably coupled to one another via a cam-slot assembly 52including a cam pin slidably received within cam slots defined withinthe proximal flange portion 43 a, 45 a of at least one of the jawmembers 42, 44, respectively, to enable pivoting of jaw member 42relative to jaw member 44 and distal segment 34 of shaft 30 between aspaced-apart position (e.g., an open position of end effector assembly40) and an approximated position (e.g., a closed position of endeffector assembly 40) for grasping tissue between tissue-contactingsurfaces 46, 48. As an alternative to this unilateral configuration, abilateral configuration may be provided whereby both jaw members 42, 44are pivotable relative to one another and distal segment 34 of shaft 30.

In embodiments, longitudinally-extending knife channels 49 (only knifechannel 49 of jaw member 44 is illustrated; the knife channel of jawmember 42 is similarly configured) are defined through tissue-contactingsurfaces 46, 48, respectively, of jaw members 42, 44. In suchembodiments, a knife assembly (not shown) including a knife tube (notshown) extending from the housing through shaft 30 to end effectorassembly 40 and a knife blade (not shown) disposed within end effectorassembly 40 between jaw members 42, 44 is provided to enable cutting oftissue grasped between tissue-contacting surfaces 46, 48 of jaw members42, 44, respectively. The knife tube is operably coupled to a knifedrive sub-assembly (not shown) of gearbox assembly 100 at a proximal endthereof to enable selective actuation to, in turn, reciprocate the knifeblade between jaw members 42, 44 to cut tissue grasped betweentissue-contacting surfaces 46, 48.

Referring still to FIG. 1A, a drive rod 484 is operably coupled tocam-slot assembly 52 of end effector assembly 40, e.g., engaged with thecam pin thereof, such that longitudinal actuation of drive rod 484pivots jaw member 42 relative to jaw member 44 between the spaced-apartand approximated positions. More specifically, urging drive rod 484proximally pivots jaw member 42 relative to jaw member 44 towards theapproximated position while urging drive rod 484 distally pivots jawmember 42 relative to jaw member 44 towards the spaced-apart position.However, other suitable mechanisms and/or configurations for pivotingjaw member 42 relative to jaw member 44 between the spaced-apart andapproximated positions in response to selective actuation of drive rod484 are also contemplated. Drive rod 484 extends proximally from endeffector assembly 40 through shaft 30 and into the housing wherein driverod 484 is operably coupled with a jaw drive sub-assembly (not shown) ofgearbox assembly 100 to enable selective actuation of end effectorassembly 40 to grasp tissue therebetween and apply a closure forcewithin an appropriate jaw closure force range.

Tissue-contacting surfaces 46, 48 of jaw members 42, 44, respectively,are at least partially formed from an electrically conductive materialand are energizable to different potentials to enable the conduction ofelectrical energy through tissue grasped therebetween, althoughtissue-contacting surfaces 46, 48 may alternatively be configured tosupply any suitable energy, e.g., thermal, microwave, light, ultrasonic,ultrasound, etc., through tissue grasped therebetween for energy-basedtissue treatment. Instrument 10 defines a conductive pathway (not shown)through the housing and shaft 30 to end effector assembly 40 that mayinclude lead wires, contacts, and/or electrically-conductive componentsto enable electrical connection of tissue-contacting surfaces 46, 48 ofjaw members 42, 44, respectively, to an energy source (not shown), e.g.,an electrosurgical generator, for supplying energy to tissue-contactingsurfaces 46, 48 to treat, e.g., seal, tissue grasped betweentissue-contacting surfaces 46, 48.

Gearbox assembly 100 is disposed within the housing and, as noted above,includes an articulation sub-assembly 200, a knife drive sub-assembly(not shown), and a jaw drive sub-assembly (not shown). Articulationsub-assembly 200, as detailed below, is operably coupled between firstand second rotational inputs, respectively, provided to gearbox assembly100, and articulation cables 38 such that, upon receipt of appropriateinputs into the first and/or second rotational inputs, articulationsub-assembly 200 manipulates articulation cables 38 to articulate endeffector assembly 40 in a desired direction, e.g., to pitch and/or yawend effector assembly 40.

The knife drive sub-assembly is operably coupled between a thirdrotational input provided to gearbox assembly 100 such that, uponreceipt of appropriate input into the third rotational input, the knifedrive sub-assembly manipulates the knife tube to reciprocate the knifeblade between jaw members 42, 44 to cut tissue grasped betweentissue-contacting surfaces 46, 48.

The jaw drive sub-assembly is operably coupled between a fourthrotational input provided to gearbox assembly 100 and drive rod 484 suchthat, upon receipt of appropriate input into the fourth rotationalinput, the jaw drive sub-assembly pivots jaw members 42, 44 between thespaced-apart and approximated positions to grasp tissue therebetween andapply a closure force within an appropriate closure force range.

Gearbox assembly 100 is configured to operably interface with a roboticsurgical system 1000 (FIG. 1B) when instrument 10 is mounted on roboticsurgical system 1000 (FIG. 1B), to enable robotic operation of gearboxassembly 100 to provide the above-detailed functionality, e.g., toprovide the rotational inputs to gearbox assembly 100. However, it isalso contemplated that gearbox assembly 100 be configured to interfacewith any other suitable surgical system, e.g., a manual surgical handle,a powered surgical handle, etc. For the purposes herein, roboticsurgical system 1000 (FIG. 1B) is generally described.

Turning to FIG. 1B, robotic surgical system 1000 is configured for usein accordance with the present disclosure. Aspects and features ofrobotic surgical system 1000 not germane to the understanding of thepresent disclosure are omitted to avoid obscuring the aspects andfeatures of the present disclosure in unnecessary detail.

Robotic surgical system 1000 generally includes a plurality of robotarms 1002, 1003; a control device 1004; and an operating console 1005coupled with control device 1004. Operating console 1005 may include adisplay device 1006, which may be set up in particular to displaythree-dimensional images; and manual input devices 1007, 1008, by meansof which a person, e.g., a surgeon, may be able to telemanipulate robotarms 1002, 1003 in a first operating mode. Robotic surgical system 1000may be configured for use on a patient 1013 lying on a patient table1012 to be treated in a minimally invasive manner. Robotic surgicalsystem 1000 may further include a database 1014, in particular coupledto control device 1004, in which are stored, for example, pre-operativedata from patient 1013 and/or anatomical atlases.

Each of the robot arms 1002, 1003 may include a plurality of members,which are connected through joints, and mounted device which may be, forexample, a surgical tool “ST.” One or more of the surgical tools “ST”may be instrument 10 (FIG. 1A), thus providing such functionality on arobotic surgical system 1000.

Robot arms 1002, 1003 may be driven by electric drives, e.g., motors,connected to control device 1004. Control device 1004, e.g., a computer,may be configured to activate the motors, in particular by means of acomputer program, in such a way that robot arms 1002, 1003, and, thus,their mounted surgical tools “ST” execute a desired movement and/orfunction according to a corresponding input from manual input devices1007, 1008, respectively. Control device 1004 may also be configured insuch a way that it regulates the movement of robot arms 1002, 1003and/or of the motors.

With reference to FIGS. 2-7, articulation sub-assembly 200 of gearboxassembly 100 is shown generally including a proximal base assembly 210,an intermediate base assembly 220, a distal base assembly 230, fourproximal gear assemblies 240, 250, 260, 270, two coupling gears 280, 290four distal gear assemblies configured as lead screw assemblies 340,350, 360, 370 (although other suitable distal gear assemblies are alsocontemplated), and four guide dowels 380. As an alternative or inaddition to coupling gears 280, 290, belts may be utilized to providethe coupling. Likewise, other gearing components detailed herein may bereplaced or supplemented with the use of belts instead of directlymeshed gears, without departing from the present disclosure. Further, inembodiments, multiple gears (and/or belts) may be provided in place ofsingle gears (and/or belts) to provide a desired amplification orattenuation effect.

Each of the proximal, intermediate, and distal base assemblies 210, 220,230, respectively, includes a base plate 212, 222, 232 defining fourapertures 214, 224, 234 arranged in a generally square configuration.Bushings 216, 226, 236 are engaged within the apertures 214, 224, 234 ofeach of proximal, intermediate, and distal base assemblies 210, 220,230, respectively.

Each proximal gear assembly 240, 250, 260, 270 includes a gear shaft 242defining an input 244 at a proximal end thereof. However, only twoinputs 244 are needed and, indeed, only two are utilized, as detailedbelow. Thus, in some embodiments, only two of the proximal gearassemblies, e.g., proximal gear assemblies 240, 250, include inputs 244while the other two proximal gear assemblies, e.g., proximal gearassemblies 260, 270, do not. Each proximal gear assembly 240, 250, 260,270 further includes an output 246 at a distal end thereof. A spur gear248 is mounted on the respective gear shaft 242 of each proximal gearassembly 240, 250, 260, 270. Proximal gear assemblies 240, 250, 260, 270are arranged to define a generally square configuration such that thespur gear 248 of each proximal gear assembly 240, 250, 260, 270,includes two adjacent spur gears 248, e.g., a vertically-adjacent spurgear 248 and a horizontally-adjacent spur gear 248, and adiagonally-opposed spur gear 248. One pair of diagonally-opposed spurgears 248, e.g., spur gears 248 of proximal gear assemblies 240, 260,are longitudinally offset relative to the other pair ofdiagonally-opposed spur gears 248, e.g., spur gears 248 of proximal gearassemblies 250, 270. More specifically, spur gears 248 of proximal gearassemblies 240, 260 are more-distally disposed as compared to spur gears248 of proximal gear assemblies 250, 270.

The utilized inputs 244 (or inputs 244 provided, where only two areprovided), e.g., the inputs 244 of proximal gear assemblies 240, 250,extend proximally into a corresponding bushing 216 disposed within anaperture 214 of base plate 212 of proximal base assembly 210. In thismanner, the two inputs 244 are positioned at a proximal end ofarticulation sub-assembly 200 to receive two rotational inputs forarticulation, e.g., from a robotic surgical system 1000 (FIG. 1B). Theoutput 246 of each proximal gear assembly 240, 250, 260, 270 extendsdistally into a corresponding bushing 226 disposed within an aperture224 of base plate 222 of intermediate base assembly 220. As detailedbelow, this enables the output 246 of each proximal gear assembly 240,250, 260, 270 to provide a rotational output to a corresponding leadscrew assembly 340, 350, 360, 370, respectively.

Continuing with reference to FIGS. 2-7, the two coupling gears 280, 290operably couple the spur gears 248 of each diagonally-opposed pair ofspur gears 248. More specifically, the more-distal coupling gear 280 isdisposed in meshed engagement with the more-distally disposed spur gears248 of proximal gear assemblies 240, 260, while the more-proximalcoupling gear 290 is disposed in meshed engagement with themore-proximally disposed spur gears 248 of proximal gear assemblies 250,270.

As a result of the above-detailed configuration, for example, arotational input provided to input 244 of proximal gear assembly 240rotates output 246 and spur gear 248 of proximal gear assembly 240 in afirst direction to, in turn, rotate coupling gear 280 in a second,opposite direction which, in turn, rotates spur gear 248 and output 246of proximal gear assembly 260 in the first direction. Further, asanother example, a rotational input provided to input 244 of proximalgear assembly 250 rotates output 246 and spur gear 248 of proximal gearassembly 250 in a first direction to, in turn, rotate coupling gear 290in a second, opposite direction which, in turn, rotates spur gear 248and output 246 of proximal gear assembly 270 in the first direction.Thus, only two rotational inputs are required to provide a rotationaloutput at the output 246 of each proximal gear assembly 240, 250, 260,270: one to the input 244 of proximal gear assembly 240 or proximal gearassembly 260, and the other to the input 244 of proximal gear assembly250 or proximal gear assembly 270. As noted above, only two inputs 244thus need be provided, e.g., input 244 of proximal gear assembly 240 andinput 244 of proximal gear assembly 250.

Each lead screw assembly 340, 350, 360, 370 includes a lead screw 342defining a proximal input end 343 and a distal dock end 345. Each leadscrew assembly 340, 350, 360, 370 further includes a collar 346 operablythreadingly engaged about the corresponding lead screw 342 such thatrotation of the lead screw 342 translates the corresponding collar 346longitudinally therealong. The proximal input end 343 of the lead screw342 of each lead screw assembly 340, 350, 360, 370 extends proximallyinto a corresponding bushing 226 disposed within an aperture 224 of baseplate 222 of intermediate base assembly 220 wherein the proximal inputend 343 is operably coupled with the output 246 of a correspondingproximal gear assembly 240, 250, 260, 270 such that rotation of outputs246 effect corresponding rotation of lead screws 342. The distal dockend 345 of the lead screw 342 of each lead screw assembly 340, 350, 360,370 extend distally into and is rotationally seated within acorresponding bushing 236 disposed within an aperture 234 of base plate232 of distal base assembly 230.

Referring still to FIGS. 2-7, lead screw assemblies 340, 350, 360, 370,similarly as with proximal gear assemblies 240, 250, 260, 270, arearranged to define a generally square configuration such that the leadscrew 342 of each lead screw assembly 340, 350, 360, 370, includes twoadjacent lead screws 342, e.g., a vertically-adjacent lead screw 342 anda horizontally-adjacent lead screw 342, and a diagonally-opposed leadscrew 342. The lead screws 342 of each diagonally-opposed pair of leadscrews 342 define opposite thread-pitch directions. For example, leadscrew 342 of lead screw assembly 340 may define a right-handedthread-pitch while the diagonally-opposite lead screw 342 of lead screwassembly 360 defines a left-handed thread-pitch. Similarly, lead screw342 of lead screw assembly 350 may define a right-handed thread-pitchwhile the diagonally-opposite lead screw 342 of lead screw assembly 370defines a left-handed thread-pitch.

As noted above, each collar 346 is operably threadingly engaged about acorresponding lead screw 342 such that rotation of the lead screw 342translates the corresponding collar 346 longitudinally therealong. Eachcollar 346 includes a ferrule 348 configured to engage a proximal endportion of one of the articulation cables 38 (see FIG. 3), e.g., via acrimped hook-slot engagement or other suitable engagement (mechanicalfastening, adhesion, welding, etc.). Thus, distal translation of acollar 346 slackens the corresponding articulation cable 38 by pushingthe corresponding articulation cable 38 in a distal direction, whileproximal translation of a collar 346 tensions the correspondingarticulation cable 38 by pulling the corresponding articulation cable 38in a proximal direction.

The four guide dowels 380 are engaged and extend between intermediateand distal base assemblies 320, 330, respectively, and are arranged in agenerally square configuration. Each guide dowel 380 extends through asleeve 349 of a collar 346 of a corresponding lead screw assembly 340,350, 360, 370. Guide dowel 380 guide translation of collars 346 alonglead screws 342 and inhibit rotation of collars 346 relative to leadscrews 342.

Turning to FIG. 8, in conjunction with FIG. 3, in order to pitch endeffector assembly 40 (FIG. 1), collars 346 of lead screw assemblies 340,350 are translated in a similar manner to actuate the upper pair ofarticulation cables 38 (FIG. 3) in a similar manner while collars 346 oflead screw assemblies 360, 370 are translated similarly to one anotherbut opposite of the collars 346 of lead screw assemblies 340, 350 suchthat the lower pair of articulation cables 38 (FIG. 3) are actuated in asimilar manner relative to one another but an opposite manner relativeto the upper pair of articulation cables 38. Referring to FIG. 9, inconjunction with FIG. 3, with respect to yaw articulation of endeffector assembly 40 (FIG. 1), collars 346 of lead screw assemblies 340,370 are translated in a similar manner to actuate the right pair ofarticulation cables 38 (FIG. 3) in a similar manner while collars 346 oflead screw assemblies 350, 360 are translated similarly to one anotherbut opposite of the collars 346 of lead screw assemblies 340, 370 suchthat the left pair of articulation cables 38 (FIG. 3) are actuated in asimilar manner relative to one another but an opposite manner relativeto the right pair of articulation cables 38.

With general reference to FIGS. 2-9, as demonstrated above, the collars346 of opposing diagonal pairs of collars 346 always move in oppositedirections relative to one another to effect articulation, regardless ofwhether of pitch and/or yaw articulation is desired and regardless ofthe direction of articulation, e.g., up pitch, down pitch, left yaw,right yaw, or combinations thereof. As also detailed above, a rotationalinput provided to input 244 of proximal gear assembly 240 or proximalgear assembly 260 provides a similar rotational output at the output 246of both proximal gear assembly 240 and proximal gear assembly 260 due tothe coupling thereof via coupling gear 280 and, thus, lead screwassemblies 340, 360 receive similar inputs from proximal gear assemblies240, 260, respectively. However, since the thread-pitch of the leadscrews 342 of lead screw assemblies 340, 360 are opposite one another,the similar inputs provided thereto effect opposite translation of thecollars 346 thereof. Likewise, a rotational input provided to input 244of proximal gear assembly 250 or proximal gear assembly 270 provides asimilar rotational output at both outputs 246 due to the couplingthereof via coupling gear 290 and, thus, lead screw assemblies 350, 370receive similar inputs from proximal gear assemblies 250, 270,respectively, to, in turn, effect opposite translation of the collars346 thereof. Thus, by controlling the directions of two rotationalinputs (one to the input 244 of proximal gear assembly 240 or proximalgear assembly 260, and the other to the input 244 of proximal gearassembly 250 or proximal gear assembly 270), pitch and/or yawarticulation in any suitable direction may be achieved.

Turning now to FIGS. 10 and 11, pre-tensioning articulation cables 38(FIG. 3) facilitates accurate articulation of end effector assembly 40(FIG. 1) and retention of end effector assembly 40 (FIG. 1) in position(whether articulated or aligned). In order to pre-tension articulationcables 38 (FIG. 3), prior to insertion of coupling gears 280, 290 intoengagement between the spur gears 248 of each diagonally-opposed pair ofspur gears 248, a first opposing diagonal pair of collars 346, e.g.,collars 346 of lead screw assemblies 340, 360, are pulled proximally ina similar manner to tension the corresponding articulation cables 38(FIG. 3) to a pre-tension threshold. Collars 346 may be translatedmanually, automatically, or semi-automatically using appropriatefixturing (not shown). A suitable force sensing mechanism (not shown)may be utilized to determine the tension on articulation cables 38 (FIG.3) such that articulation cables 38 (FIG. 3) are pre-tensioned to thepre-tension threshold.

Once the pre-tension threshold has been reached, coupling gear 280 isinserted into meshed engagement with spur gears 248 of proximal gearassemblies 240, 260. With coupling gear 280 inserted in this manner,thereby coupling proximal gear assemblies 240, 260, the articulationcables 38 (FIG. 3) associated with lead screw assemblies 340, 360 aremaintained in the pre-tensioned condition due to the fact that leadscrew assemblies 340, 360 act in opposite directions and, thus, inhibitde-tensioning of one another.

With reference to FIGS. 2-7, similarly with respect to coupling gear 290and proximal gear assemblies 250, 270, the second opposing diagonal pairof collars 346, e.g., collars 346 of lead screw assemblies 350, 370, arepulled proximally in a similar manner to tension the correspondingarticulation cables 38 (FIG. 3) to the pre-tension threshold. Once thepre-tension threshold has been reached, coupling gear 290 is insertedinto meshed engagement with spur gears 248 of proximal gear assemblies250, 270 to thereby maintain the corresponding articulation cables 38(FIG. 3) in the pre-tensioned condition.

Referring to FIGS. 12-16, another surgical instrument provided inaccordance with the present disclosure is shown generally identified byreference numeral 500. Surgical instrument 500 is similar to surgicalinstrument 10 (FIG. 1) and, thus, only differences therebetween aredescribed in detail below while similarities are summarily described oromitted entirely.

Surgical instrument 500 generally includes a housing 502, a shaft 503extending distally from housing 502, an end effector assembly 504extending distally from shaft 503, and a gearbox assembly 510 disposedwithin housing 502 and operably associated with end effector assembly504.

Gearbox assembly 510 of surgical instrument 500 is disposed withinhousing 502 and includes an articulation sub-assembly 520, a knife drivesub-assembly (not explicitly identified), and a jaw drive sub-assembly(not explicitly identified). Articulation sub-assembly 520 is similar toarticulation sub-assembly 200 of surgical instrument 10 (FIGS. 1-11), asdetailed above, except as explicitly contradicted below. Morespecifically, articulation sub-assembly 520 differs in the configurationand manner in which pre-tensioning is achieved.

With respect to articulation sub-assembly 520, the distal dock end 545of the lead screw 542 of each lead screw assembly 540 extends distallyinto and is rotationally seated within a corresponding bushing 536disposed within an aperture 534 of base plate 532 of distal baseassembly 530. Distal base assembly 530 defines an internally-threadednut 538 disposed within each aperture 534 distally-adjacent the busing536 thereof. A set screw 550 is threadingly engaged within eachinternally-threaded nut 538. For the purposes herein, “set screw”includes any adjustable setting structure including, for example, athreaded set screw (as illustrated), a lock pin, etc. Set screws 550,thus, may be rotationally driven proximally to abut bushing 536 and urgebushings 536 proximally which, in turn, urge the lead screws 542proximally. The proximal urging of lead screws 542 moves collars 546proximally, thereby pulling the associated articulation cables (notshown; see articulation cables 38 (FIG. 3)) proximally to tension thearticulation cables. Thus, by rotationally driving set screws 550, thearticulation cables may be tensioned to the pre-tensioned threshold.

Access holes 560 defined within housing 502 enable access to set screws550, e.g., via a suitable driver tool (not shown), to rotationally driveset screws 550 and thus, establish an appropriate pre-tension on thearticulation cables (not shown; see articulation cables 38 (FIG. 3)).Thus, with respect to instrument 500, pre-tensioning of the articulationcables is accomplished after assembly is complete, although otherconfigurations are also contemplated.

FIGS. 17 and 18 illustrate another gearbox assembly 600 configured, forexample, for use with surgical instrument 10 (FIG. 1). Gearbox assembly600 includes an articulation sub-assembly 700, a knife drivesub-assembly (not shown), and a jaw drive sub-assembly (not shown).Articulation sub-assembly 700 is similar to articulation sub-assembly200 of surgical instrument 10 (FIGS. 1-11), as detailed above, except asexplicitly contradicted below. More specifically, articulationsub-assembly 700 differs in the configuration of proximal gearassemblies 740, 750, 760, 770. That is, rather than including spur gears248 directly coupled between the input 244 and the correspondingcoupling gear 280, 290 as with articulation sub-assembly 200 (FIGS.2-7), proximal gear assemblies 740, 750 of articulation sub-assembly 700include gear sets 741, 751 disposed between inputs 744 and couplinggears 780, 790.

Gear set 741 includes a first gear 743 engaged to input 744 of proximalgear assembly 740. First gear 743 is disposed in meshed engagement witha second gear 745 of different size such that a rotational inputprovided to input 744 rotates first gear 743 to, in turn, rotate secondgear 745. A coupling gear 780 is fixed relative to second gear 745 andis disposed in meshed engagement with third gears 747, 767 of proximalgear assemblies 740, 760 (of different size than coupling gear 780) suchthat rotation of second gear 745 rotates third gears 747, 767. Thirdgears 747, 767 are engaged with the lead screws 842 of the correspondinglead screw assemblies 840, 860. Thus, proximal gear assemblies 740, 760operate similarly as detailed above with respect to surgical instrument10 (FIGS. 1-11) except that amplification or attenuation of the torqueand/or motion imparted to lead screw assemblies 840, 860 based upon arotational input to input 744 is provided. The particular amplificationor attenuation of the torque and/or motion is based upon the gear ratiosof gears 743, 745, 747, 767.

Gear set 751 is similar to gear set 741 and includes a first gear 753engaged to input 744 of proximal gear assembly 750. First gear 753 isdisposed in meshed engagement with a second gear 755 of different sizewhich, in turn, is fixed relative to a coupling gear 790. Coupling gear790 is disposed in meshed engagement with third gears 757, 777 ofproximal gear assemblies 750, 770 (of different size than coupling gear790) such that rotation of second gear 755 rotates third gears 757, 777.Third gears 757, 777 are engaged with the lead screws 852 of thecorresponding lead screw assemblies 850, 870. Thus, proximal gearassemblies 750, 770 likewise provide amplification or attenuation of thetorque and/or motion imparted to lead screw assemblies 850, 870.

It will be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplifications of variousembodiments. Those skilled in the art will envision other modificationswithin the scope and spirit of the claims appended thereto.

1. An articulation assembly for a surgical instrument, comprising:first, second, third, and fourth lead screw assemblies, each lead screwassembly including a lead screw and a collar operably engaged about thelead screw such that rotation of the lead screw translates the collarabout the lead screw, first, second, third and fourth articulationcables operably coupled to the collars of the first, second, third, andfourth lead screw assemblies, respectively, such that proximal movementof one of the collars about the respective lead screw tensions thecorresponding articulation cable and such that distal movement of one ofthe collars about the respective lead screw de-tensions thecorresponding articulation cable; first, second, third and fourthproximal gear assemblies coupled to the lead screws of the first,second, third, and fourth lead screw assemblies, respectively; a firstcoupling gear coupling the first and third proximal gear assemblies withone another to maintain a pre-tension on the first and thirdarticulation cables; and a second coupling gear coupling the second andfourth proximal gear assemblies with one another to maintain apre-tension on the second and fourth articulation cables.
 2. Thearticulation assembly according to claim 1, wherein the lead screws ofthe first and third lead screw assemblies define opposite thread-pitchesrelative to one another and wherein the lead screws of the second andfourth lead screw assemblies define opposite thread-pitches relative toone another.
 3. The articulation assembly according to claim 2, whereinthe first coupling gear couples the first and third proximal gearassemblies such that the lead screws of the first and third lead screwassemblies are rotated in similar directions and, thus, such that thecollars of the first and third lead screw assemblies are moved inopposite directions, and wherein the second coupling gear couples thesecond and fourth proximal gear assemblies such that the lead screws ofthe second and fourth lead screw assemblies are rotated in similardirections and, thus, such that the collars of the second and fourthlead screw assemblies are moved in opposite directions.
 4. Thearticulation assembly according to claim 1, wherein the first couplinggear couples the first and third proximal gear assemblies such that thelead screws of the first and third lead screw assemblies are rotated insimilar directions, and wherein the second coupling gear couples thesecond and fourth proximal gear assemblies such that the lead screws ofthe second and fourth lead screw assemblies are rotated in similardirections.
 5. The articulation assembly according to claim 1, furthercomprising: a proximal base assembly, an intermediate base assembly, anda distal base assembly, wherein the first, second, third, and fourthproximal gear assemblies extend between the proximal and intermediatebase assemblies, and wherein the first, second, third, and fourth distalgear assemblies extend between the intermediate and distal baseassemblies.
 6. The articulation assembly according to claim 1, whereineach of the first, second, third, and fourth proximal gear assembliesincludes a gear shaft defining an output configured to drive rotation ofthe corresponding lead screw, and a spur gear engaged about the gearshaft, wherein the first coupling gear is disposed in meshed engagementwith the spur gear of the first and third proximal gear assemblies andwherein the second coupling gear is disposed in meshed engagement withthe spur gear of the second and fourth proximal gear assemblies.
 7. Thearticulation assembly according to claim 1, wherein a first gear setoperably couples the first and third proximal gear assemblies with thefirst coupling gear, the first gear set configured to amplify orattenuate the outputs from the first and third proximal gear assembliesto the corresponding lead screws relative to the input to the firstproximal gear assembly, and wherein a second gear set operably couplesthe second and fourth proximal gear assemblies with the second couplinggear, the second gear set configured to amplify or attenuate the outputsfrom the second and fourth proximal gear assemblies to the correspondinglead screws relative to the input to the second proximal gear assembly.8. A surgical instrument, comprising: a housing; a shaft extendingdistally from the housing, the shaft including an articulating section;an end effector assembly extending distally from the shaft, the endeffector assembly including first and second jaw members, at least thefirst jaw member movable relative to the second jaw member from aspaced-apart position to an approximated position to grasp tissuetherebetween; and an articulation assembly disposed within the housing,the articulation assembly configured to articulate the end effectorassembly relative to the housing via first, second, third, and fourtharticulation cables extending through the shaft, the articulationassembly including: first, second, third, and fourth lead screwassemblies, each lead screw assembly including a lead screw and a collaroperably engaged about the lead screw such that rotation of the leadscrew translates the collar about the lead screw, wherein the first,second, third and fourth articulation cables are operably coupled to thecollars of the first, second, third, and fourth lead screw assemblies,respectively, such that proximal movement of one of the collars aboutthe respective lead screw tensions the corresponding articulation cableand such that distal movement of one of the collars about the respectivelead screw de-tensions the corresponding articulation cable; first,second, third and fourth proximal gear assemblies coupled to the leadscrews of the first, second, third, and fourth lead screw assemblies,respectively; a first coupling gear coupling the first and thirdproximal gear assemblies with one another to maintain a pre-tension onthe first and third articulation cables; and a second coupling gearcoupling the second and fourth proximal gear assemblies with one anotherto maintain a pre-tension on the second and fourth articulation cables.9. The surgical instrument according to claim 8, wherein the lead screwsof the first and third lead screw assemblies define oppositethread-pitches relative to one another and wherein the lead screws ofthe second and fourth lead screw assemblies define oppositethread-pitches relative to one another.
 10. The surgical instrumentaccording to claim 9, wherein the first coupling gear couples the firstand third proximal gear assemblies such that the lead screws of thefirst and third lead screw assemblies are rotated in similar directionsand, thus, such that the collars of the first and third lead screwassemblies are moved in opposite directions, and wherein the secondcoupling gear couples the second and fourth proximal gear assembliessuch that the lead screws of the second and fourth lead screw assembliesare rotated in similar directions and, thus, such that the collars ofthe second and fourth lead screw assemblies are moved in oppositedirections.
 11. The surgical instrument according to claim 8, whereinthe first coupling gear couples the first and third proximal gearassemblies such that the lead screws of the first and third lead screwassemblies are rotated in similar directions, and wherein the secondcoupling gear couples the second and fourth proximal gear assembliessuch that the lead screws of the second and fourth lead screw assembliesare rotated in similar directions.
 12. The surgical instrument accordingto claim 8, wherein the articulation assembly further comprises: aproximal base assembly, an intermediate base assembly, and a distal baseassembly, wherein the first, second, third, and fourth proximal gearassemblies extend between the proximal and intermediate base assemblies,and wherein the first, second, third, and fourth distal gear assembliesextend between the intermediate and distal base assemblies.
 13. Thesurgical instrument according to claim 8, wherein each of the first,second, third, and fourth proximal gear assemblies includes a gear shaftdefining an output configured to drive rotation of the correspondinglead screw, and a spur gear engaged about the gear shaft, wherein thefirst coupling gear is disposed in meshed engagement with the spur gearof the first and third proximal gear assemblies and wherein the secondcoupling gear is disposed in meshed engagement with the spur gear of thesecond and fourth proximal gear assemblies.
 14. The surgical instrumentaccording to claim 8, wherein a first gear set operably couples thefirst and third proximal gear assemblies with the first coupling gear,the first gear set configured to amplify or attenuate the outputs fromthe first and third proximal gear assemblies to the corresponding leadscrews relative to the input to the first proximal gear assembly, andwherein a second gear set operably couples the second and fourthproximal gear assemblies with the second coupling gear, the second gearset configured to amplify or attenuate the outputs from the second andfourth proximal gear assemblies to the corresponding lead screwsrelative to the input to the second proximal gear assembly.
 15. Arobotic surgical system, comprising: a surgical robot including arobotic arm configured to provide first and second rotational outputs;and a surgical instrument releasably mountable on the robotic arm, thesurgical instrument including: a housing; a shaft extending distallyfrom the housing, the shaft including an articulating section; an endeffector assembly extending distally from the shaft, the end effectorassembly including first and second jaw members, at least the first jawmember movable relative to the second jaw member from a spaced-apartposition to an approximated position to grasp tissue therebetween; andan articulation assembly disposed within the housing, the articulationassembly configured to articulate the end effector assembly relative tothe housing via first, second, third, and fourth articulation cablesextending through the shaft, the articulation assembly including: first,second, third, and fourth lead screw assemblies, each lead screwassembly including a lead screw and a collar operably engaged about thelead screw such that rotation of the lead screw translates the collarabout the lead screw, wherein the first, second, third and fourtharticulation cables are operably coupled to the collars of the first,second, third, and fourth lead screw assemblies, respectively, such thatproximal movement of one of the collars about the respective lead screwtensions the corresponding articulation cable and such that distalmovement of one of the collars about the respective lead screwde-tensions the corresponding articulation cable; first, second, thirdand fourth proximal gear assemblies coupled to the lead screws of thefirst, second, third, and fourth lead screw assemblies, respectively,the first and second input gears configured to receive the first andsecond rotational outputs, respectively; a first coupling gear couplingthe first and third proximal gear assemblies with one another tomaintain a pre-tension on the first and third articulation cables; and asecond coupling gear coupling the second and fourth proximal gearassemblies with one another to maintain a pre-tension on the second andfourth articulation cables.
 16. The robotic surgical system according toclaim 15, wherein the lead screws of the first and third lead screwassemblies define opposite thread-pitches relative to one another andwherein the lead screws of the second and fourth lead screw assembliesdefine opposite thread-pitches relative to one another.
 17. The roboticsurgical system according to claim 16, wherein the first coupling gearcouples the first and third proximal gear assemblies such that the leadscrews of the first and third lead screw assemblies are rotated insimilar directions and, thus, such that the collars of the first andthird lead screw assemblies are moved in opposite directions, andwherein the second coupling gear couples the second and fourth proximalgear assemblies such that the lead screws of the second and fourth leadscrew assemblies are rotated in similar directions and, thus, such thatthe collars of the second and fourth lead screw assemblies are moved inopposite directions.
 18. The robotic surgical system according to claim15, wherein the articulation assembly further comprises: a proximal baseassembly, an intermediate base assembly, and a distal base assembly,wherein the first, second, third, and fourth proximal gear assembliesextend between the proximal and intermediate base assemblies, andwherein the first, second, third, and fourth distal gear assembliesextend between the intermediate and distal base assemblies.
 19. Therobotic surgical system according to claim 15, wherein each of thefirst, second, third, and fourth proximal gear assemblies includes agear shaft defining an output configured to drive rotation of thecorresponding lead screw, and a spur gear engaged about the gear shaft,wherein the first coupling gear is disposed in meshed engagement withthe spur gear of the first and third proximal gear assemblies andwherein the second coupling gear is disposed in meshed engagement withthe spur gear of the second and fourth proximal gear assemblies.
 20. Therobotic surgical system according to claim 15, wherein a first gear setoperably couples the first and third proximal gear assemblies with thefirst coupling gear, the first gear set configured to amplify orattenuate the outputs from the first and third proximal gear assembliesto the corresponding lead screws relative to the input to the firstproximal gear assembly, and wherein a second gear set operably couplesthe second and fourth proximal gear assemblies with the second couplinggear, the second gear set configured to amplify or attenuate the outputsfrom the second and fourth proximal gear assemblies to the correspondinglead screws relative to the input to the second proximal gear assembly.